Chucky

Antimagic Susceptibility. Chucky is incapacitated while in the area of an antimagic field. If targeted by dispel magic, Chucky must succeed on a Constitution saving throw against the caster’s spell save DC or fall unconscious for 1 minute.

A Toy by any other name. While Chucky remains motionless, he is indistinguishable from a child's doll.

Multiattack. Chucky makes two bite attacks or uses Mind Bolt twice.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (1d6 + 3) piercing damage plus 7 (2d6) psychic damage.

Mind Bolt. Ranged Spell Attack: +8 to hit, range 60 ft., one target. Hit: 10 (3d6) psychic damage.

Chucky has 3 legendary actions.

Chucky casts  Polymorph (2 Actions)

Chucky casts a Cantrip from the following list: 
Vicious Mockery
Primal Savagery
Thunderclap
Gust

Arcane Rebound. If Chucky makes a successful saving throw against a spell that targets only itself, or a spell attack misses it, he can use his reaction to cause the spell to rebound back at the caster. The spell then targets the caster instead of Chucky. If the spell forced a saving throw, the caster makes its own save. If the spell was an attack, the attack roll is re-rolled against the caster.

Chucky regains 3 legendary actions at the start of his turn.